Sooooo....can you actually fill a gas tank with water and start cutting and welding on it? Or is that BS advise that will get me on the 6 o'clock news? I have a junk tank that I would like to use the sending unit out of. I'd like to cut out the mounting point and weld it into an aux tank that does not have a sending unit.

Some radiator shops will repair a tank. most have a hot tank to clean them. I usually first do a good job of getting out all the gas then rinse a couple times with HOT soapy water, then you need to fill with water so there is no air left inside and if necessary have a hose running more water inside. the varnish build up inside will burn. I usually gas weld or braze a patch. years ago I repaired the original gas tank for Ford's director of SVO_Ford racing 's 427 Cobra. IT was all soldered. I heated up all the seams and wire brushed away as much solder as possible then spot brazed about 2 inches apart the entire seam then re soldered it over the top , Air plus gasoline and varnish residue and a torch will poof, too much air and a bang. the trick is to keep air out. I have made a plywood and 2 X 4 box and lined it with plastic to be able to have a tank of water like a radiator shop uses a couple times.

I WAS considering an update to EFI with an in tank electric fuel pump and was told by a large performance parts supplier that "all I had to do was wash out the tank 2-3 times, wave a torch over the filler hole and it would poof once and it would be safe to weld on". Not something I want to try with my nicely painted and very costly '32 Ford gas tank any day of the week. Then there is my original personal body pieces still all stuck nicely together without any embedded pieces of stray metal.

Get an unused/new tank or at least have an experienced radiator shop do your clean out and 'poof test'. Additionally, you can probably find a replacement sender at a supplier like Rock Auto and reasonably priced.

__________________
Irelands child

The Following User Says Thank You to Irelands child For This Useful Post:

Last time I had to modify a fuel cell, we washed it out well, then I inerted it under an argon purge and started the grinding/welding processes (using a Tig). And yes, most radiator shops, the big ones, also do gas tanks, they can boil them out and flush, and do mods.

you get a poof when there is only about a Quart of air and it has an escape route out the filler spout. The natural gas company used to do safety demonstrations at schools. and other events, they had a model house, about a 2 ft cube that snaped together, he would put in 4 or 5 drops of gasoline, wait about a minute while he talked then ignite it with a spark plug and It made a loud bang like an M 80 firecracker and blew the house apart. I have seen engines with the valve covers and oil pan all ballooned out from gasoline in the oil and the vapor ignited thru a backfire and bad pvc valve

I have repaired a few by just washing it out a few times,,, If you use saftey it can be done..Wash it out really good three or four times and you will know when it's ready...you can pass the torch over the filler to check it.. But I never did get a poof when I did the ones I did,,If it still smell's bad after you wash it out, Wash it again and again,,,Good Luck, Just Becareful....

If your not sure, Don't do it...

The Following User Says Thank You to NEW INTERIORS For This Useful Post:

I have repaired a few by just washing it out a few times,,, If you use saftey it can be done..Wash it out really good three or four times and you will know when it's ready...you can pass the torch over the filler to check it.. But I never did get a poof when I did the ones I did,,If it still smell's bad after you wash it out, Wash it again and again,,,Good Luck, Just Becareful....

If your not sure, Don't do it...

Absolutely. I recently finished doing an EFI swap into a 62 Vette tank. washed the heck out of it with soap and water several times, dried with a rag blown around inside via air hose, then ran the exhaust side of my shop vac in the tank for 15 minutes or so until there was zero moisture or fuel smell. cut the opening with side grinder and cut off wheel, then mig welded a reinforcement plate under the opening for the new cover plate to screw to. no "poof" and I'm still intact. If the tank has varnish and residue in it, you need a new tank anyway. if not, then just clean the heck out of it and go to work.

Russ

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The Following User Says Thank You to Northstar T For This Useful Post:

I have since spoke with a good friend who has welded several when full of water. While I agree that parts are cheap ( compared to lifeflight and ER), there are NO known sources for 70s Dodge cab tank sending units. If you can find them NOS, they are $300 and north. So having a functional unit (I rebuilt the one in the now defunct tank) is quite a find. As you know Chrysler used a different ohm range on their senders and having the same will allow for switching the gauge between the two tanks. Personally I would rather avoid cutting the mounting flange out of the junk tank because I don't want to be "that guy" and will take a look at fabbing a suitable mounting system. It WOULD be a lot easier though. Fortunately the aux tank has been dry for a few years and appears devoid of lingering vapor, though I will certainly treat it as a potential bomb. Thanks for your input....it helps to keep me off the news.

The radiator shop here also repairs and or modifies gas tanks also,they flush it out and put a rubber hose in it,and hook it to a running car for about five minutes,the carbon monoxide from the exhaust takes all the oxygen out of the tank,they weld on it with a torch and a mig,seen it done many times,I personally would just buy new,but that's just me...

A friend lives in the 'Mountains" near Sant Cruz Calif, and has had mountain Lions go thru their yard and doesn't own a Gun. He got a trap from the county animal control ( Dog Catcher) officer and caught a skunk. He called them back and they said you caught it it's YOURS. He took a hose from the shop vacuum, hooked it up to the exhaust on his wife's new Honda, thru a blanket over the trap and after half an hour the skunk was not even dizzy. He had to start up his old 78 dodge van to send the skunk to stinks no more land.
Ps We can see the tops of the Grand Teton Mountains out the kitchen window, REAL mountains

.......... No exhaust fumes to worry about..Really not sure what people think they are doing by doing this..

Mostly just luck so far I would guess. I have heard of doing this as well, but do agree with you. Wash it a couple times, 'poof' it with a torch then go to work. Regardless, still not something I'm willing to do.

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